Chinese DG3804 GMT Service, Teardown and my Review!

I decided to purchase a couple of these Chinese made DG3804 GMT movements several months ago.  Mostly because I had a customer ask me specifically to use one in a custom watch that he intended to use as items he could give away to his customers.  To be honest, I’ve seen these floating around the internet, but never got my hands on one, as most of my customers don’t purchase these off market watches.

I was able to order the movements, and all the other parts, like hands, cases, bands and dials from ebay.  Click here, to check out my article on getting these delivered to your doorstep in two weeks!

Once they came in, I spent a few days getting things ready for my customer, and since I had ordered some extras, (Mostly because I wasn’t sure about the quality of the watch movement), I tackled my customer’s watch.

With the extra parts, I decided to make one for myself, to try and get some experience to see if this watch, the parts that go along with it, and its quality, would hold up to my use.

Initially, I had no intentions on having to teardown and do a complete service on this watch movement.  To be honest, I have not had good experience doing service on these very inexpensive watches.  I have had my taste of cheap Invicta Chinese movements that break easily.  And to be honest, I recommend that you take the time to read this or watch the video so that you get a good idea of the hours I spent on this, and my review and opinion at the end. 

In a nutshell, the watch I made for my customer has not bee used yet.  Still in its box, and waiting for him to do what ever he wants to.  Mine, on the other hand, has been through the small battles that I use a watch with.  Riding motorcycles, swimming, yard work, etc.  I don’t take my watch off.  If it is going to last, it had better make it more than a month on my wrist.

Sadly, this watch started giving me some issues after about three weeks.  It was time for me to tear it down and find out why!

Watch the Video Here!

The Teardown of its Parts!

Breaking down the watch is the easy part of course.  I’ve listed in this article, the tools and supplies you will need, check those out if you don’t have them.

This watch movement is not terribly complicated.  I do recommend that you have a parts tray available for the teardown so that when you take the parts out of the watch, you can have a secure and safe place for them.

To do the teardown, make sure you have a set of watchmakers screwdrivers and tweezers.  You will need several different size drivers and a find nose pair of tweezers.

I always start with the teardown of the upper plate.  This is wear the setting gears are located.  The setting gears of a watch work both automatically and manually allowing the movement to adjust the date on its own, as well as allowing you to manually set the time and date.

In this particular watch, because of the GMT function, you will have several extra gears and wheels to deal with.  Make sure you take pictures or videos of the parts and where they are to be located for future reference.

Once you have the setting system and date ring out, its time to flip the watch over, and begin the task of disassembly of the train on the watch movement.  First, start with the balance cock and wheel.  I remove it as one piece in the video, and that is the common way of doing it.  Although you can perform your teardown in any order you are comfortable.

Once the balance is out, the next step is to remove the pallet fork and fork bridge.  Then you can move on to the lower plate, and remove the entire train and mainspring barrel.  Note, that on better quality watches, where are normally two or more bridges that hold the parts in the frame of the watch movement, however, on the DG308 GMT, this is not the case.

The DG308 uses one lower bridge that holes not just the train together, but additionally the winding gears for the mainspring.  This will complicate the assembly of the watch as you’ll need to spend extra time getting each of the gears pinions into their corresponding jewels correctly.

Cleaning all the parts

I’m not going to cover the cleaning of all the parts in this article, nor will I be showing you how to do it in the video.  However, click here, to see my article and video on watch parts cleaning. It is an example of a pocket watch, but the same holds try for wristwatches and most clocks.  Check it out.

Getting ready for the Watch Train Assembly

the DG3804 assembly is a bit more difficult than a Rolex 3135, 3035 or an ETA 2408.  Keep that in mind, because I really had to fight with this watch to get it back together.

All the parts should be cleaned, dried and ready to go back together.  

The first part of this watch that I put back together was the train, and the mainspring winding gears.  I decided to tackle this first, because I like to make sure the watch runs and runs well, before I assemble any of the complications (i.e. GMT, Chronograph functions).  A Working watch movement is the heart of the entire watch.  If it doesn’t run and keep time, nothing else on the watch is going to work well.

On this DG3804, you have to put the center wheel in first, then its bridge to hold it in position.  From there, you will have to add and lockdown simultaneously, the train, (3 more gears), two winding gears for the auto and manual winding, and the mainspring barrel.  This is time consuming because, the gears are not manufactured perfectly, to hold themselves in the jewels.  So, as you try and put the gears in position, they will wobble, fall, come out of the jewels, and generally give you grief to do the assembly.

To overcome this, I get all the gears in place, then put the lower bridge in place, but loosely.  I can then put one screw in, at the position where I’m going to start making sure the gear pinions seat with their corresponding jewels.  By loosing holding the movement, and using a pair of fine tweezers, I can make my way from one gear to the next, and gently putting each gear in position, and tightening the bridge plate slightly as I move along, until the furthest gear is seated, and the remaining bridge screws can be set in the plate and tightened.

Once all the gears are set, the bridge is seated and screwed down, I can them move on to testing the movement and making sure that all the gears work and move freely and correctly.  After it meets that requirement, I can then oil the jewels and pinions on the train and give it a final test.

Assembly of the Setting System

The DG3804 GMT movement has a slightly more complex setting system then does a standard watch movement.  This is because of the Military GMT Gears, and of course, because the designer of this watch had to add an extra setting gear somewhere in the watch as a bonus!

There are three small setting gears.  One is thicker then the other two (which are identical).  The larger or thicker gear makes contact with the clutch.

The two smaller gears are standard setting wheels and operate both the hour wheel for time setting, as well as the interaction with the manual date wheel set gear that floats along the upper part of the watch frame.

In addition, the automatic date set wheel and a small gear, that interacts with the GMT wheel are set and aligned together, as in the video.  

The most difficult part of the setting system to assemble, at least on the movement that I used in this instructional video, was the click-spring for the date-ring click.  The slot for the spring is not cut well.  The upper part of it is rounded off and this makes the click spring want to “pop” out of the slot.  It make it difficult for me to set it in place and keep it their long enough to set the date ring in position.  This, however, has to be done that way, and you, like me may get a bit frustrated.  Just keep going, it will stay eventually.

Once everything is set in place, and nothing is popping out of position, you can add the setting plate above all the gears and additionally, this holds the date ring in place nicely.

The setting system is held in with three screws, and the plate covers the gears and wheels perfectly, and this allows the setting of the watch to work perfectly.

During my work on this watch, while putting the cannon pinion back onto the movement, I discovered that it was very loose.  This should fit snug and tightly onto the center wheel.  Since my was loose, I used some cutters to squeeze it VERY Gently, and make it a tighter fit onto the center wheel.  This was one of the problems I had with this watch initially, and I’m glad I tore it down and discovered why it wasn’t working correctly.

Set Dial and Recase

Again, I’m not going to go into detail about setting up the dial and hands.  However, I do want to touch on a reminder that once the dial is on the watch, and you are ready to set the hands…  Keep in mind that you are adding four hands in layers to this watch.  If you have a dial that has raised indicators, you must make sure that none of the hands touch the indicators.

From there, set the next hand, and test, set the next hand and set.  The final hand is the second hand.  Set that and test.  Make sure that none of the hands hit each other.

I also need to express this warning.  Because the DG308 GMT is not perfectly machined, there is some looseness to the parts.  Make sure when testing the hands that you wind the hands both clockwise and counter clockwise.  Depending on how loose any of the gears or wheels are, hands will move differently while turning in different directions.

Click here, to see my video on assembly of the dial and hands for the DG3804.

After Assembly, what do I think of the DG3804?

OK.  I spent over ten hours on this.  Tearing it down, cleaning it, servicing it and making and editing the video…  What a couple of days!

Let me explain what I think of this watch movement so far.

First, I told you that my watch, after three weeks was loosing 15 minutes a day.  I believe this was due to two problems with the watch.  First, but not as important, the mainspring had no spring oil in it.  This concerns me because as the mainspring winds and unwinds, it will generate friction, and metal fragments over time.  If it was oiled from the factory, this would be less of an issue over an extended period of time.

Secondly, the cannon pinion was Extremely loose on my example.  This I’m sure, allowed some slippage in the watches operation.  Even while I was wearing it, the cannon pinion being loose, would allow for too much slop in the operation, and the hands could slip out of position, or not turn at all.  This is an easy fix, but the watch does have to be disassembled for both these issues to be corrected.

The case, hands and dial are really good.  I would not hesitate to use them again, and knowing that they will work with ETA and Citizen mechanical movements is great too.  Just make sure you purchase the correct dials and hands for the case and movement you are using.  The case, after I changed the gaskets tested water tight to 90 feet.  I’m good with that!

On a scale of 1 to 10…  This watch movement is a 7.2.  Most of it is manufactured very well.  I’m happy with the fit and function of most parts.  However, the train is difficult to reassemble, and the parts on the train are a bit too loose for my liking.  However, now that it has been cleaned, serviced and fixed, I’m interested to see how it runs for the next four weeks as I again put it through its paces.  

Stay tuned, because I’m going to do a follow up on this and give it a final review.

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